An important processes to understand when installing a transaxle is shift linkage adjustment. This page provides an outline for one of the methods of adjusting an H pattern shift linkage. Keep in mind there are other opinions on how to adjust H pattern shift linkage, this method below is our recommendation, a method that works for us all the time.
Length Adjustment
Adjusting the shift linkage length is pretty straight-forward. With the transmission securely installed in the car, put the transmission in neutral and adjust the length of the shift tube using the adjustment nuts located in the middle of the shift tube (shown to the right). With the nut loose, screw the adjustment threads in or out to the proper length. The length of the shift tube must be adjusted so the shift socket is exactly in the middle of the mount hole (below right) when when the shift tube is connected to the transaxle shaft with the set-bolt tightened.
Once you have adjusted the length correctly, don’t tighten the jam nut on the shift tube yet. The next step is to install the cockpit shifter mechanism. Notice there is a little slop in the mounting holes of the stick shift base (found on most aftermarket shifters). Bolt the shifter base down so the chassis shifter mount with the adjustment bolts in the neutral position (centered). This provides a little fine tuning later if needed, front to back. After the shifter base is firmly installed and tightened, the next step is to adjust the shift tube clocking, which can be tricky if you don’t know how.
It’s time to find first gear. Since the shift tube adjustment nut is still loose, tighten it temporarily, then use the stick shift to put the car in gear, what you believe to be 1st gear. At this point you can be in 1st gear or 3rd gear, because we haven’t clocked the shift tube yet.
Finding first gear may take a couple of attempts of loosening and tightening the shift shaft adjustment nut, changing the shift tube clocking to find 1st gear. Usually this isn’t a problem since there are only two gears you can be in when you push the stick shift forward. See the rotational clocking diagram to help find 1st gear (below right). Just remember, 1st locates the set bolt at about 12 o’clock. If you don’t know how to find 1st gear you may want to ask a friend that knows to help.
Shift Shaft Clocking
After you confirm you have the transaxle in 1st gear, you’re ready for the final adjustment, the fine tune clocking of the shaft. This fine tuning allows your shifter to work flawlessly, smoothly shifting into each gear. This adjustment takes patience, a helper, and sometimes a little trial and error adjustments. Here’s what works for us.
1. With the transaxle in 1st gear, loosen the shift shaft adjustment nut.
2. Push the stick shift lever all way FORWARD and to the LEFT, as if you are holding it firmly in 1st gear. Have someone hold it there firmly.
3. While the shifter is being held in 1st gear place, use two wrenches to tighten the shift tube jam nuts. One wrench will hold the rear section of the shift shaft steady (the side going to the transaxle). The other wrench tightens the jam nut on the front section of the shaft. Make sure you don’t torque the rear portion of the shift tube to the transaxle when tightening the nut with the other wrench. Insure the rear portion of the shaft is held with a wrench to prevent torque being applied to the rear tube, in either direction ….. as best possible.
Checking for Gears
After you do the steps above check all gears to insure all gears can be found. Do not force the shifter to find gears, they should be easy to find with the clutch pushed in. If all gears can be found with the engine off, it’s time to test reverse. Most shifters have a reverse lockout lever to prevent accidental reverse shifts. Pull the reverse lockout and put the transmission in reverse and test. If you have reverse, you’re good.
If you cannot find all gears, review all of the steps above and try it again. As mentioned, it may take a little trial and error. It’s rare that newbies get it right the first time. Patience is golden for shift linkage adjusting. Once you learn the knack you’ll be an authentic duner for life.
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